ABSTRACT This competing revision would support expansion of the sample inclusion criteria of the Sexual Orientation, Gender Identity, Socioeconomic Status, and Health Across the Life Course Study (SOGI-SES; 1R01HD087365-01A1). The SOGI-SES study is developing and administering a web survey to an estimated subset of 2444 sexual and gender minority respondents, as well as 1500 cisgender heterosexuals, in the National Longitudinal Study of Adolescent to Adult Health (Add Health) Wave V Program Project sample. To date, Add Health has completed one in-school, four in-home, and one web-based waves of interviews with a nationally representative sample of approximately 20,000 US adolescents who, at study entry in 1994-95, were in grades 7-12.The overall goal of the SOGI-SES project is to capture and disseminate socioeconomic and developmental milestone information pertinent to the health and development of sexual and gender minorities. Despite the importance of SES to health, knowledge about factors that pattern resources and strains across sexual and gender minority groups is incomplete, largely because of the absence of appropriate and high quality data. In the SOGI-SES study, sexual orientation identity and gender identity were to be used to define sexual and gender minorities (SGMs) for sampling purposes (total expected n with 80% response rate = 3155). In this revision we propose to expand the sample inclusion criteria to encompass individuals with nonconforming gender expression and/or with discordant lifetime sexual partnering and sexual orientation identity (i.e., individuals who consistently identify as ?completely heterosexual,? but report same-sex partners). Based on Wave V data we estimate 722 unique individuals in these two groups. Assuming an 80% response rate, with this supplement we would add 578 respondents to our originally proposed sample. A growing body of research suggests that nonconforming gender expression is associated with increased risk of violence and harassment, poorer mental health, and employment-related inequities. Literature has also indicated that gender nonconformity, a visible stigma, may be even more relevant for psychological health than same-sex sexual orientation. Discordant heterosexual identity and same-sex behavior has also been associated with poorer mental health, possibly due to the stress of concealment. Expanding our sample to include these important and understudied groups will substantially enhance the SOGI-SES project by providing unique information about minorities who have been followed for more than 20 years, from adolescence into adulthood, and who were not originally selected into Add Health based on sexual orientation, gender identity, or gender expression. The project will test hypotheses derived from Minority Stress Theory to understand the implications of developmental and socioeconomic factors for mental health. Expanded sampling criteria will enable us to enhance the field by providing new information about the intersections of gender, gender expression, sexual orientation, and same-sex partnering and their contributions to socioeconomic status and health.